With thin film growth technology and device material development, a light emitting device such as light emitting diode using III-V or II-VI group compound semiconductor materials or a laser diode may realize various colors including red, green and blue and such a light emitting device may realize a white light having good luminescence efficiency by using a phosphor material or combining colors. Also, the light emitting device may have advantages of low power consumption, a semipermanent life span of usage, a rapid response speed and good eco-friendliness, compared with a conventional light source such as a fluorescent lamp and an incandescent lamp.
As a result, the light emitting device has been increasingly applied to a transmission module of optical communication means, a light emitting diode backlight substituting for a cold cathode fluorescence lamp (CCFL) composing a backlight of a liquid crystal display (LCD) device, a white light emitting diode lighting device, a headlight of a vehicle and a streetlight.